Efficacy and Safety of Frontline Tislelizumab in Patients With de Novo Hodgkin Lymphoma Unsuitable for Standard Frontline Chemotherapy

Approximately two-thirds of patients with Hodgkin lymphoma (HL) can be cured with standard frontline chemotherapy with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD). The majority of new patients present in the second and third decade of life, but at least 25% of de novo cases are in patients older than 65. Elderly patients with HL display dismal outcomes for several reasons: the disease is implicitly more aggressive than in younger adults, with an advanced stage in at least two-thirds of cases and the presence of multiple risk factors for poor outcome (according to the International Prognostic Score). Moreover, patients may show impaired organ function that require chemotherapy dose reductions, treatment delays or drug withdrawal. Given the difficulty of delivering of full treatment doses to elderly patients and to those with relevant medical comorbidities, there is a need for new and better tolerated agents in this context. Given the difficulty of delivering of full treatment doses to elderly patients and to those with relevant medical comorbidities, there is a need for new and better tolerated agents in this context. Importantly, no single agent has received approval for this kind of patients, and drugs like gemcitabine and bendamustine - both active in relapsed patients with limited toxicity - have limitations in their prescription. The anti-CD30 immunoconjugate agent brentuximab vedotin (BV) applied in patients older than 60 years and considered unsuitable for frontline chemotherapy, yielded an overall response of 92%, with 73% of patients achieving a complete remission and a median duration of response of 9.1 months. Immune checkpoint inhibitors, namely nivolumab and pembrolizumab, have been largely tested in patients with relapsed and refractory HL failing both autologous stem cell transplant and BV. Both agents display efficacy in this context, with significant rates of objective responses, which appear to be durable. Along with an acceptable safety profile, both agents have been approved in relapsed and refractory HL, providing a good treatment option for heavily pretreated patients. Tislelizumab (T, BGB-A317) is a humanized IgG4 mAb with high affinity and specificity for programmed cell death protein 1 (PD1), showing a superior antitumor activity compared to nivolumab in mice transplanted with human cancer cells and peripheral blood mononuclear cells. High response rates have been reported in Chinese HL patients who have failed or were ineligible to autologous transplantation, including a complete response rate of 61% and a partial response rate of 24%. Investigators postulate that an induction based on single-agent tislelizumab can be a feasible chemo-free treatment strategy to be offered to patients with de novo HL who are unsuitable for a chemotherapy-based frontline approach. The study also addresses biological evaluation of biomarkers in the tumor clone and in the microenvironment at baseline and their possible correlation with patients' outcome and responses.